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The Passive House standard has slowly made its way around the globe, since its inception in

the early 1990’s. Founded from research into the relationship between thermal comfort and

passive design, the standard’s success is testament to the strength of concept.

Schools Infrastructure New South Wales have commissioned this report into the case for

developing schools in NSW to the Passive House standard, using a current project as a

prototype to test the concept. This report aims to establish the benefits of doing so, alongside

the costs and risk, and to ascertain whether there is a rationale to further pursue this particular

design approach as a means to enhance the offering of high quality, low-energy and healthy

environments for children to learn.

This report also outlines the local market readiness to deliver Passivhaus sufficient to meet the

needs of the government, meeting the key objective to “deliver the very best school

infrastructure so that the NSW public education system is one of the finest in the world”. By

providing a robust and complete discussion on the opportunities and benefits, alongside a

balanced view on the impacts to design and construction; it is envisaged that, with this

information, decision-makers in the sector can confidently pursue the standard for greater

benefit.

Higher standards of building construction quality are required to benefit the overall health and

wellbeing of society.

As we spend about 90% of our time indoors, the quality of the interior environment is more

important than ever, and for schools – spaces that serve vulnerable and developing humans

– the quality of environment can have considerable impact on the occupants.

The primary reasons for the application of Passivhaus fall largely into three areas: health,

economy and energy efficiency. One of the key strengths is that, to date, it is the only standard

where the built performance matches the design predictions quite closely, i.e. that there is no

performance gap.

The site delivery of projects to the Passive House standard is by far the most critical aspect in

terms of delivering to the requisite cost target. From experience, site impacts can entirely

undermine any perceived cost benefits achieved and/or predicted during the design stage.

This might include;

• Inadequate contractor engagement, including insufficient appreciation of the impact of design specifics (details) and product substitutions;

• Inadequate sub-contractor education and training;

• Changes to programme (lead time) or availability of specified products, required to achieve the performance parameters.

As such, performance targets must be clearly specified in early briefing, and held as firm targets throughout documentation and tender.

Two factors are key when comparing Passivhaus to standard practice:

1. The locally appropriate response for the particular building, including climate, typical

construction methods and skill availability;

2. The comparable baseline for individual projects, i.e. building code compliance or 5 Star Green Star.

Some of the key benefits of building to the Passive House standard are direct and measurable.

Direct savings include:

• reductions in energy consumption / costs;

• reduced ongoing maintenance;

• simplified or smaller infrastructure, including air conditioning.

Other cost savings are indirect or external to occupants and some may require a broader assessment of the system in which they occur. These might include:

• Increased attention of students, leading to potential for improved academic outcomes;

• Cost reductions due to build quality and durability;

• Costs reductions from streamlining the approach to complementary rating systems, such as Green Star;

• Potentially reduced programme costs, with the opportunity for enhanced

outcomes from prefabrication or modularisation, and associated site time savings.

Both the local and international experiences on Passive House is that, in a new market, there

is cost premium for increased specifications on the basic building elements. This includes

improved window specifications, the introduction of ventilation systems and increased

dedication to correctly delivering a continuous thermal and airtight envelope (including

thermal bridging).

Many international markets have worn the path of a maturing market and eventually seen the

Passive House market grow to support the delivery of cost parity or cheaper project.

Although the ultimate goal might be to deliver Passive House-type projects at nil capital

premium, early projects in any region should expect a premium of up to 10%; however, this

depends very much on the comparative baseline and the required improvements. In any

case, the life cycle costs assessment is positive.

The provision of high-quality buildings has the potential to impact on factors far beyond the

reach of traditional economic models, or simply hard to include in a model with discrete

boundaries. Further discussion is required on how factors such as the following might be

captured:

1. Comfort;

2. Health, including reduced absence of students and staff;

3. Occupant satisfaction and pride of place;

4. Impact on the local health sector;

5. Other social parameters, including benefits to children’s education, worker productivity and staff health.

It is important to note that the Passivhaus approach differs fundamentally from standard

building delivery; the delivery of excellent comfort and IEQ is the very basis on which the

building is developed. The core driver of buildings for human health in occupation means that

buildings often cannot be compared on metrics alone as the qualitative measures are not

adequately represented. A building might show low energy use, and delivery very poorly on

the provision of adequate internal conditions, let alone those optimised for health and

learning.

It is highly recommended that SINSW builds school buildings to the Passive House standard.

Download the full report here